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Monday, November 19, 2018

The present phase of stagnation in the foundations of physics is not normal

Nothing is moving in the foundations of physics. Oneexperimentaftertheotheris returningnull results: No new particles, no new dimensions, no new symmetries. Sure, there are some anomalies in the data here and there, and maybe one of them will turn out to be real news. But experimentalists are just poking in the dark. They have no clue where new physics may be to find. And their colleagues in theory development are of no help.

I think stagnation describes it better. And let me be clear that the problem with this stagnation is not with the experiments. The problem is loads of wrong predictions from theoretical physicists.

The problem is also not that we lack data. We have data in abundance. But all the data are well explained by the existing theories – the standard model of particle physics and the cosmological concordance model. Still, we know that’s not it. The current theories are incomplete.

We know this both because dark matter is merely a placeholder for something we don’t understand, and because the mathematical formulation of particle physics is incompatible with the math we use for gravity. Physicists knew about these two problems already in 1930s. And until the 1970s, they made great progress. But since then, theory development in the foundations of physics has stalled. If experiments find anything new now, that will be despite, not because of, some ten-thousands of wrong predictions.

Ten-thousands of wrong predictions sounds dramatic, but it’s actually an underestimate. I am merely summing up predictions that have been made for physics beyond the standard model which the Large Hadron Collider (LHC) was supposed to find: All the extra dimensions in their multiple shapes and configurations, all the pretty symmetry groups, all the new particles with the fancy names. You can estimate the total number of such predictions by counting the papers, or, alternatively, the people working in the fields and their average productivity.

They were all wrong. Even if the LHC finds something new in the data that is yet to come, we already know that the theorists’ guesses did not work out. Not. A. Single. One. How much more evidence do they need that their methods are not working?

This long phase of lacking progress is unprecedented. Yes, it has taken something like two-thousand years from the first conjecture of atoms by Democritus to their actual detection. But that’s because for most of these two-thousand years people had other things to do than contemplating the structure of elementary matter. Like, for example, how to build houses that don’t collapse on you. For this reason, quoting chronological time is meaningless. We should better look at the actual working time of physicists.

I have some numbers for you on that too. Oh, yes, I love numbers. They’re so factual.

According to membership data from the American Physical Society and the German Physical Society the total number of physicists has increased by a factor of roughly 100 between the years 1900 and 2000.* Most of these physicists do not work in the foundations of physics. But for what publication activity is concerned the various subfields of physics grow at roughly comparable rates. And (leaving aside some bumps and dents around the second world war) the increase in the number of publications as well as in the number of authors is roughly exponential.

Now let us assume for the sake of simplicity that physicists today work as many hours per week as they did 100 years ago – the details don’t matter all that much given that the growth is exponential. Then we can ask: How much working time starting today corresponds to, say, 40 years working time starting 100 years ago. Have a guess!

Answer: About 14 months. Going by working hours only, physicists today should be able to do in 14 months what a century earlier took 40 years.

Of course you can object that progress doesn’t scale that easily, for despite all the talk about collective intelligence, research is still done by individuals. This means processing time can’t be decreased arbitrarily by simply hiring more people. Individuals still need time to exchange and comprehend each other’s insights. On the other hand, we have also greatly increased the speed and ease of information transfer, and we now use computers to aid human thought. In any case, if you want to argue that hiring more people will not aid progress, then why hire them?

So, no, I am not serious with this estimate, but I it explains why the argument that the current stagnation is not unprecedented is ill-informed. We are today making more investments into the foundations of physics than ever before. And yet nothing is coming out of it. That’s a problem and it’s a problem we should talk about.

I’ve recently been told that the use of machine learning to analyze LHC data signals a rethinking in the community. But that isn’t so. To begin with, particle physicists have used machine learning tools to analyze data for at least three decades. They use it more now because it’s become easier, and because everyone does it, and because Nature News writes about it. And they would have done it either way, even if the LHC would have found new particles. So, no, machine learning in particle physics is not a sign of rethinking.

Another comment-not-a-question I constantly have to endure is that I supposedly only complain but don’t have any better advice for what physicists should do.

First, it’s a stupid criticism that tells you more about the person criticizing than the person being criticized. Consider I was criticizing not a group of physicists, but a group of architects. If I inform the public that those architects spent 40 years building houses that all fell to pieces, why is it my task to come up with a better way to build houses?

Second, it’s not true. I have spelled out many times very clearly what theoretical physicists should do differently. It’s just that they don’t like my answer. They should stop trying to solve problems that don’t exist. That a theory isn’t pretty is not a problem. Focus on mathematically well-defined problems, that’s what I am saying. And, for heaven’s sake, stop rewarding scientists for working on what is popular with their colleagues.

I don’t take this advice out of nowhere. If you look at the history of physics, it was working on the hard mathematical problems that led to breakthroughs. If you look at the sociology of science, bad incentives create substantial inefficiencies. If you look at the psychology of science, no one likes change.

Developing new methodologies is harder than inventing new particles in the dozens, which is why they don’t like to hear my conclusions. Any change will reduce the paper output, and they don’t want this. It’s not institutional pressure that creates this resistance, it’s that scientists themselves don’t want to move their butts.

How long can they go on with this, you ask? How long can they keep on spinning theory-tales?

I am afraid there is nothing that can stop them. They review each other’s papers. They review each other’s grant proposals. And they constantly tell each other that what they are doing is good science. Why should they stop? For them, all is going well. They hold conferences, they publish papers, they discuss their great new ideas. From the inside, it looks like business as usual, just that nothing comes out of it.

Great article Sabine. I have been saying these things to my friends for a while. I even tried to work on non-standard ideas during and after my PhD. I wrote some single author papers with new ideas some of which got published (e.g. arXiv:1206.2530). But the end result of all this is that your career gets negatively affected. I have not been able to get a good research position because most of the work I did was not standard ideas in contemporary theoretical physics. In such a scenario, how can you encourage the young physicists to work on new ideas because these are the people who would bring about change in the field.

I see the stagnation is a good word to describe situation. Usually it has predicted a breaktrough sooner or later. Nowadays we have so much discussions on non-significant hypothetical details so that new, maybe fruitful, points of view have stayed drowned...

I guess it was Mao Tse Dung who said before everything gets completely dark it becomes black. However, I don’t think things are this dire; things are not looking good in some ways, but it is not as if nothing has happened.

(Note: I am a mathematical biologist working on very different problems, so take my comment with many grains of salt).

My rough impression is that there are still reasonably interesting questions which remain in QFT in general, and the standard model in particular. People like Peter Woit have suggested that studying the mathematical structures in these objects may be difficult, but a possible source of inspiration. There are also many open problems in "applications" of fundamental physics which, to me at least, are still very appealing theoretically. Thermodynamics and nonequilibrium physics (particularly condensed matter theories) still have many important unsolved problems which are amenable to theoreticians and which would be invaluable for understanding the implications of particles and other fundamental objects on meaningful scales in other areas of science. Of course from the other side there are interesting questions regarding gravity and GR, in addition to possible alternatives or generalisations.

All in all I think there is still plenty of work to be done, and I think the obsession with a Theory of Everything is silly. Many meaningful implications of even quantum mechanics haven't been worked out, and such work could help broaden the horizons for theoretical physics altogether.

I have the impression, the problem arises from the hybris, new physics could be invented like a piece of art. for a certain period, there have been some guiding priciples and sufficient experimental data to make successful predictions for new discoveries. But looked more closely, in many cases these rather filled gaps of already working theories. Then these theories seemed to imply (beautiful) extensions or complements. Testing these has been justified of course, but unsuccessful. But meanwhile these extensions have turned into poking in the (vast) dark.It may be more helpful to guide experiments not to test specific but arbitrary unlikely assumptions, but rather to find the deviations and surprises, that might guide better new theory attempts. As I see it, in more productive times there have been more unexplained experimental findings as guidance. To achieve this premature reliance on / usage of still unproven assumptions (e. g. too specific assumptions on dark matter) should be avoided. For the individual researcher the pressure to publish with focus on quantity over quality or originality is a problem, which worsens the situation. I see no easy remedy, but clearly enhancements are needed, and these will only come when the deficits of the current course becomes obvious - hopefully not to aid those wanting to starve out science. Science will never be straightforward.

"Yes, it has taken something like two-thousand years from the first conjecture of atoms by Democritus to their actual detection. But that’s because for most of these two-thousand years people had other things to do than contemplating the structure of elementary matter. Like, for example, how to build houses that don’t collapse on you."

I think this has more to do with society allowing enough room for a system that's not based on authority. You can't do science in a Taliban-like society. Science can only work if arguments from authority are depreciated. The reason why early scientific work around the year 1000 in the Islamic world was not followed by a scientific revolution there, was due to religious authorities imposing their opposition to the methods that had yielded results earlier there which involved engaging in arguments regardless of authority.

The reason why Western civilization ended up giving rise to the scientific revolution has a lot more to do with the total economic collapse of society in the early 14th century than with economic growth and the well being of the population. It was the great famine of 1315 that was later followed by black death epidemics that undermined the traditional religious and secular authorities.

https://en.wikipedia.org/wiki/Great_Famine_of_1315–17

"In a society whose final recourse for all problems had been religion, and Roman Catholicism was the only tolerated Christian faith, no amount of prayer seemed effective against the causes of the famine. That undermined the institutional authority of the Church and helped lay the foundations for later movements that were deemed heretical by the Church, as they opposed the papacy and blamed the perceived failure of prayer upon corruption within the Church."

A century later the printing press was invented that helped make the Reformation possible and later also the scientific revolution.

And today we have the internet which is doing today what the printing press did before. Bringing information to the masses. Back then the authorities didn't like it. Today science ignores the serious thinkers not within their closed ranks.I say "emperor's clothes'" to ideas like vacuum energy, expansion of space, inflation theory. How can serious scientists believe this stuff.Think again, outside the box, but keep it real. Only real things happen in the universe.I say again "emperor's clothes'!

It's not just that scientists don't want to move their butts, although that's undoubtedly part of it. It's also that they can't. In today's university funding system, you need grants (well, maybe you don't truly need them once you have tenure, but they're very nice to have).

So who decides which people get the grants? It's their peers, who are all working on exactly the same things that everybody is working on. And if you submit a proposal that says "I'm going to go off and work on this crazy idea, and maybe there's a one in a thousand chance that I'll discover some of the secrets of the universe, and a 99.9% chance that I'll come up with bubkes," you get turned down.

But if a thousand really smart people did this, maybe we'd actually have a chance of making some progress. (Assuming they really did have promising crazy ideas, and weren't abusing the system. Of course, what would actually happen is that the new system would be abused and we wouldn't be any better off than we are now.)

So the only advice I have is that more physicists need to not worry about grants, and go hide in their attics and work on new and crazy theories, the way Andrew Wiles worked on Fermat's Last Theorem.

Let me make an addendum to my previous comment, that I was too modest to put into it. This is roughly how I discovered the quantum factoring algorithm. I didn't tell anybody I was working on it until I had figured it out. And although it didn't take years of solitary toil in my attic (the way that Fermat's Last Theorem did), I thought about it on and off for maybe a year, and worked on it moderately hard for a month or two when I saw that it actually might work.

The situaton reminds me in some kind of the Merowingians, the royal elite and guidung clan of the Francish Empire in the 7th and 8th century: they were so eager killing rivals and hatching plots to stretch their individual power, that they had no time left to rule their empire properly and left that to their 'hausmeiers' (i.e. kinda primeministers), till those finally took the power, dropping the Royals off and depositing them in monestaries - and cemeteries... The most famous and successful 'hausmeier' then was the grandfather of Charlemagne, founding a new and even more powerful empire stretching over almost whole of europe... :-)

Maybe we also need a new and more poweful paragon in theoretical physics while the merowingian physicists keep on eager arguing and publishing over and over again...

Bee, many points you make are correct, but not the first sentence: "Nothing is moving in the foundations of physics." This is true for experiment, but not for theory. There exists at least one idea predicting that general relativity and the standard model, with its particles, gauge groups and forces, form the final description; and the idea seems to suggest how to calculate the parameters of the standard model. The idea unifies the concordance model with the standard model. The idea agrees with observed data and does not predict any new particles. There are also many testable predictions.

I know much more than I'm allowed to say. Technology always outpaces science. No new technologies employ the W or Z or quarks. It is all standard QM. The standard model has produced NO "works" as people like to say.

I don't want to let experiment off the hook so easily. Theorists need a motivation, a problem to solve. This can be either an inconsistency, an open question, an unexplained observation, or more often a combination of these. Two examples: Hey, there noise in the microwave spectrum! Why? Hey, neutrinos left-handed! Why? Usually observations play an important role in providing clues for theorists. In recent years, experimentalists have not been able to provide very many of these clues. Is it because they are misguided by theorists (Sabine's explanation), underfunded, unlucky, or uncreative? I could argue for each of these except unlucky.

An argument for uncreative is a little bit similar to Sabine's criticism of theorists: It's easier to refine an existing measurement using existing data than it is to propose, get funded, and do something risky. Time-to-graduation becomes a distribution with a very long tail when a grad student is not risk-averse. We could fix this, perhaps, by relaxing the requirements for theses, funding, etc. But as in theory, experimental proposals are evaluated by physicists who only have experience doing iterations of basically the same experiments.

Your 40-years-vs-14-months argument is really clever! There is a counter-argument but it's much weaker I think. This is that physicists should never say words like "unprecedented" since they are such bad historians, having been taught a very glossy (retold) and abridged version of history. Still, I do think your argument stands.

I can second your thoughts on machine learning. ML approaches are not new to the particle physics community, and while it's nice to have in the toolbox, it's not an open frontier or a game-changer.

Science Is Getting Less Bang for Its BuckDespite vast increases in the time and money spent on research, progress is barely keeping pace with the past. What went wrong?https://www.theatlantic.com/science/archive/2018/11/diminishing-returns-science/575665/

The "publish or perish" culture, where publication becomes the GOAL of research, rather than a means to communicate is responsible for this.The stagnation in the foundations of physics is the clearest proof that "publication productivity" has zero correlation with actual scientific progress.Yet every university in every country is jumping on the publication bandwagon and creating a feedback loop to generate yet more useless publications at a higher rate.

Even if physics isn’t doing so well, perhaps other fields are doing better? We carried out similar surveys for the Nobel Prize for chemistry and the Nobel Prize for physiology or medicine. Here are the scores:.......The results are slightly more encouraging than physics, with perhaps a small improvement in the second half of the 20th century. But it is small. As in physics, the 1990s and 2000s are omitted, because the Nobel Committee has strongly preferred earlier work: Fewer prizes were awarded for work done in the 1990s and 2000s than over any similar window in earlier decades.

The picture this survey paints is bleak: Over the past century, we’ve vastly increased the time and money invested in science, but in scientists’ own judgement, we’re producing the most important breakthroughs at a near-constant rate. On a per-dollar or per-person basis, this suggests that science is becoming far less efficient.

I'm re-reading Kuhn's The Structure of Scientific Revolutions (50th anniv. edition) and it's great upon re-reading also. I wonder if stagnation eventually precipitates a crisis? I would hope so. It's interesting to me how quickly scientists like to dismiss Kuhn's ideas about the irrational nature of science and the absence of progress or cumulative science. Kuhn was a Ph.D physicist who spent a lifetime studying science in the same way that physicists study nature. He should be read and understood a lot more widely.

I am not convinced the experimentalists are entirely innocent in this either, because as Thomas Kuhn asserted, they do experiments designed support the current thinking. As a simple example, look at the delayed-choice quantum eraser experiment. The idler photons are split into two streams. One stream goes to a detector, and since it is known which slit the photon that generated the entangled pair went though, theory predicts the corresponding signal photons will show no diffraction pattern, and they do not. The other half of the idler pairs go to a mixer. The slit origin of a given generating photons of these idlers is lost, and their corresponding signal photons give a diffraction pattern, s they expected. So everyone claps themselves in the back.

In my opinion, there is a problem. Suppose only half the signal photons can give a diffraction pattern? Recall one photon went through a slit - two photons emerge from the down converter so maybe only one carries diffraction information. We can check this rather simply by blocking one of the two paths of the idler photons going to the mixer. Prior to blocking, we KNOW all the signal photons give the diffraction pattern. If knowledge of the slit has nothing to do with that and the entanglement is restricted to the conservation law, then the diffraction pattern will remain (and you will learn little more about beam splitters) so this could be fundamental experiment. From experience, if you announce something like this, you get smiles of sympathy, but nobody wants to do anything. Of course, guess how much chance you would get for funding such an experiment that is peer reviewed by those who are convinced in standard theory.

Suppose one agrees with you. It's easy to complain about how others are doing things wrong. What are you doing right? What prediction are you making that should be tested? What predictions have been made by other people who have embraced your criticisms that have not been tested?

Certainly, I certainly would love to see some fantastic theoretical breakthrough. I'd be equally happy to see an experimental observation that badly breaks the Standard Model. But neither of these have been forthcoming. Very sad.

In short, suppose you had a hundred students who reported just to you. Just exactly what guiding principle, new insight, different approach, unexplored mathematical framework would you have them start working on tomorrow? It's easy to say that people are doing things wrong. What...specifically...is right?

Millennial scientists, FTW. They've been conditioned to feel that mere participation is the same as actual achievement and that 30-hour work weeks are the same as hard work, and now it's showing, not only in our sciences, but in all our fields of study (and industry). *Everything* is stagnating because we've raised two consecutive generations of coddled, disengaged, attention-challenged humans that salivate at the sound of each text message chime. Think I'm kidding or just being a curmudgeon? Fine. But you'll be treated to watching the trend continue in the meantime... :)

I recently answered a question about wormholes on Quora by referencing one of your blog posts (http://backreaction.blogspot.com/2018/07/10-physics-facts-you-should-have.html, item #8).

In response, a doctoral candidate at a U.S. university commented that my answer was "not quite correct." His arguments were (1) There are no generic “Wormhole No-Go” theorems; (2) There are a lot of scientific papers about wormholes on the arxiv; (3) "there are meta materials which have wormhole-like non-local effects", a statement which he supported by https://www.nature.com/articles/srep12488.

So it seems like the absence of a no-go theorem, some theoretical publications, and a some clever labeling are enough to establish the existence of a cosmological entity these days. Even to a Ph.D. student in physics.

Well, it's something new, to have thousands of "models" being published. But it's also new to have a theory of almost-everything. And both developments arise from the same source, the 1970s revolution in gauge theory. That revolution produced the big synthesis that is the standard model, and it also opened the way to numerous generalizations. It just so happens that the standard model has held up empirically all that time, while none of the generalizations have been vindicated.

Nonetheless, it was important to pursue the possibilities of gauge theory (a process that remains far from over). It means that if deviations from the standard model are found, we have some idea of what they might be. And if we jump straight to the endpoint of that path - the models of string phenomenology - they are unique in showing us a kind of theory in which all the free parameters of the standard model have an explanation. There is no other theoretical framework that is remotely comparable, in the sense that it reduces to gauge field theory, but has mechanisms which determine the values of the field-theoretic parameters. So it's absolutely appropriate and essential that this line of thought be pursued, until it is verified, or falsified, or something clearly more promising turns up.

Of course, it's appropriate that people should be investigating other lines of thought at the same time. And fortunately, there are thousands of people doing just that, from the tenured physicists who pursue unconventional theories, to the outsiders on vixra and elsewhere.

There may be ways in which the overall development of fundamental physics since the 1970s has been suboptimal, or major missed opportunities. But the fact that thousands of generalizations of basic gauge theory were explored, without yet delivering any verified advance beyond the standard model, does not in itself prove a massive mistake was made. First, those possibilities deserved to be explored and had to be explored, and second, they got us to string theory, which is still the best single candidate we have for explaining the inputs to the standard model. And third, we have continued to explore other byways at the same time.

Yes, you did get it all wrong. The point is that theorists have made wrong predictions for 40 years. Yes, they have difficult problems to solve, but that doesn't explain how come all those wrong predictions. What this demonstrates very clearly is that the methods they use aren't working. I explain this in great detail in the book.

I have no idea what you are talking about. My best guess is that you try to promote your own theory of something. In this case, please read my comment rules and please continue such conversation elsewhere.

First, that's an ad hominem attack. It has nothing to do with my argument whatsoever.

Second, I have answered this question over and over again, but people either do not understand the answer or do not want to understand it. Of course I am part of the same system. I cannot change the system by changing myself. It's not possible. If you think so, you didn't understand what I am talking about. Of course I have the very problems that I talk about in my book. That's WHY I talk about them.

Third, I sent you an email about this last time you asked. You didn't respond.

A lot of people here are submitting comments to this thread in which they propose their own unified theories or approaches to quantum gravity. I do not approve such comments. Please move discussion of your personal theories elsewhere and read our comment rules. Thanks.

"The problem is also not that we lack data. We have data in abundance. But all the data are well explained by the existing theories – the standard model of particle physics and the cosmological concordance model." That sounds like a lack of data to me; a lack of useful data. 10^24 cat pictures isn't going to tell me what a toaster looks like.

Maybe the problem is not the way in which we do physics, but a more fundamental fact. It is possible (the possibility is there, I guess nobody can deny it formally) that simply we, humans, can't go forward (or too much forward) of our current status.

And I know nobody likes pessimistic conclusions but, well, I think it's a possible answer to the fact that "we are today making more investments into the foundations of physics than ever before. And yet nothing is coming out of it". It's possible the stagnation to be a some kind of esencial limit of our own physiology.

So, in summary, I'd like to know what do you think about this possible explanation to the stagnation situation (I know it's a complicated question and that to be honest even with oneself -and more in public- is very difficult). Do you think it could be the case(I only talk about the possibility) that our (advanced) monkey brain were not enough to go farther (or too much farther) no matter the time or the money we put in it.

"And let me be clear that the problem with this stagnation is not with the experiments"

And yet: I've been trying for years to find a convincing recording of a quantum eraser experiment; all I find is CGI and articles that claim other people did it. The few attempts at replication I found fail for various reasons.

There is progress in the 'foundations' going on. Here is a recent example/update... (imho).https://arxiv.org/abs/1801.06347 ("The physical origin of quantum nonlocality and contextuality", A. Cabello )

The situation you describe sounds rather like the one described in "Rigor Mortis"(RM), a few blogs back. Obviously you saw a connection, otherwise you wouldn't have written about it. That book makes a big point of the fact that bad science can poison future work by seeding wrong ideas in the literature. The awful part is that a mistake need not necessarily show itself at once (in the language of RM,the work done on corrupted cell lines didn't immediately alert researchers to the fact that they were using the wrong type of cells). Theories can be constructed around the results of bad experiments, and maybe those theories look sound, but obviously they ultimately lead to a dead end.

To me, the answer might be to re-evaluate a great deal of past work, looking for something that performed a role analogous to a critical experiment done with the wrong kind of cell.

OK, I am only an ex-chemist, but I think a good candidate might be the concept of particles that can never, ever be observed singly - quarks - even though that gave rise to the standard model which seems to hold up.

I think you are right in saying that mistakes may have been made long ago and also that quite possibly crucial insights have gotten buried somewhere in the literature. However, the experimental situation in physics is entirely different than in the life sciences (I actually go on about this in my book, in case you read this). The big issue with experiments in the life sciences is the enormous number of environmental parameters that can influence the outcome of an experiment, plus the difficulty of reproducing initial conditions (as with cell-lines and antibodies etc). These are problems that just don't exist in physics in this form.

There is nothing wrong with particles that can't be observed in isolation. I don't understand why this seems to rub so many people the wrong way. Quarks are a model that fits the data extremely well, and that's that. Whether you like this or not is totally irrelevant, what's relevant is that it works.

We've already breached the limit of usefulness of continual spaces as a mathematical modeling tool, therefore the particle desert. One simply can't go into that region of "smaller" and blindly extrapolate such an unphysical concept of continuum.Almost all the symmetries, "elementary" particles and laws are expressed in these essentially macroscopic terms, i.e. as a sort of probabilistic abstract geometry, so they have very limited applicability at "smaller" scales. Moreover, this is not a natural kind of space where everything happens, so physicists have hard times to fit it with various behavioral statistical models, sometimes conceptually very broken and misleading. But, I won't go further here on this subject.Otherwise, I wouldn't go so hard on particle physicists -- unfortunately, science is a sort of business, and we are a part of the whole educational system based mostly on economy metrics. And the subject itself is hard, it takes someone's lifetime to have a little grasp on a mainstream view of it with little to no perspective for any real advance in this area. And although 99.5 or more percents of physics "beyond" the Standard Model is sheer waste, it is rather intriguing why alternative approaches are so discouraged and rejected by the scientific community in general.And, are we really so short on new ideas, new perspectives and interpretations on ("good") old concepts ?

You already made your sentence "Focus on mathematically well-defined problems…" more explicit with “Quantum gravity, Landau Pole, non-perturbative formulation of qft…”. Is it also e.g. what you did here conveying Verlinde´s fascinating idea into a more feasible Lagrangian?

I agree with you to drop the conviction for naturalness and beauty. Let us just insert e.g. Λ and the 14 digits of the Higgs mass for now – absolutely no need to think this would be unnatural. [Maybe later theories will be capable to explain these values, but trying to do it now obviously inhibits progress.]Regarding symmetries: they popped up, but were not the major driving force to arrive at SR, GR and QFT. [Admittingly with the exception of the standard model.]In general, science always progressed when unnecessary, implicit assumptions were jettisoned.

SR was born out of the apparent conflict between Maxwell’s c=const and Galilean relativity. The solution was to jettison the implicit assumption of absolute time. Out popped Lorentz symmetry SO(3,1). To arrive at GR the assumption of a global symmetry had to be jettisoned, it became a local Lorentz symmetry.Same happened with QM. The apparent conflict between Maxwell’s smooth field and Boltzmann’s granular atoms. The solution was to jettison the assumption that a particle is exclusively a well-defined point in spacetime. A wavy character had to be added and out popped a global phase factor, the symmetry U(1). Dirac realized that QM is just a non-rel. limit, global SO(3,1) popped up in rel. QM. Next step was to make the global U(1) a local one, a gauge symmetry. Next the non-abelian cases SU(2), SU(3). [Here Yang-Mills did in QM what Cartan did 30 years earlier in GR.] Admittingly this stage of developing the standard model was driven by symmetry, but being driven and dragged away by SU(5) led to a failure.

The null result of Michelson-Morley in hindsight is explained by SR, dropping absolute time and space. All the null results today cry out for dropping another implicit assumption. You already identified one, let´s jettison the assumption of naturalness and beauty. Which one next?

I recently read your article “What Quantum Gravity Needs Is More Experiments” again. Maybe Paternostro could soon give us a hint whether gravity needs to be quantized at all.What will we do if this experiment gives a null result? When gravity is not quantized. Then we again have an apparent conflict: QM particles can be in superposition, but spacetime cannot. What will bring QM and GR together in a consistent manner, since “… particle physics is incompatible with the math we use for gravity.”?What will be the implicit assumption we need to jettison next? I think in your book there is already a clue, where you talk with George Ellis: “But if you pick up any book on quantum field theory you find nothing about the measurement problem.” I nod. “They just calculate probabilities but never discuss how the probabilities turn into measurement outcomes.” “Yes. So we need to go back [and] rethink the measurement problem.”

Dear Sabine, you write:"I have spelled out many times very clearly what theoretical physicists should do differently. It’s just that they don’t like my answer. They should stop trying to solve problems that don’t exist."And:"Developing new methodologies is harder than inventing new particles in the dozens, which is why they don’t like to hear my conclusions. Any change will reduce the paper output, and they don’t want this. It’s not institutional pressure that creates this resistance, it’s that scientists themselves don’t want to move their butts."

Sabine, you have not right to blame them, you belong to them too. For you there is no physics outside of particle physics. You write: "Nothing is moving in the foundations of physics." You don't accept the enormous change in the unification of physics (and the science as a whole).

You write: "I am afraid there is nothing that can stop them." It is also not true. The Egyptian civilization has been stopped, the Greek one, and the Roman too. They all died out. Let the Medieval Civilization of your Professors also die out. Don't care about them. They all belong already today to the (better or worse) history of science. Do care about the unified physics beyond the "particle-physics" tale. Our First Global Civilization is emerging just now. And the new "Global Science" belongs already to it today.

Yes, indeed I agree with George Ellis on that point. I believe we talked about this earlier? I suspect it actually is a mathematical inconsistency (with reductionism, which is well supported by many experiments), just that no one has yet quite managed to pin it down.

Regarding Verlinde. He is working on a well-defined problem to begin with, which is that there are many observations which are just incompatible with the standard model plus GR. I do not mean to say that every new idea must be mathematically flawless at conception. That's never been the case and requiring it would not help anyone. But it's certainly something one should work towards. My issue is primarily with theories that are neither necessary to explain observations (as with dark matter), nor necessary for mathematical consistency (as naturalness-based SM extensions).

My suggestion is to change what a PhD is. Instead of requiring a thesis or research for a PhD I would just suggest a more rigorous curriculum with just more classes in the subject area, because there is such more abundance of material to learn in each discipline. There could be another level above a PhD where some requirement for research would be done. Also, extra requirements for a PhD could be much more statistics classes.

Sabine,You wrote: “There is nothing wrong with particles that can't be observed in isolation. I don't understand why this seems to rub so many people the wrong way. Quarks are a model that fits the data extremely well, and that's that.”

It may be that some people are irritated because there seems to be a conflation of (at least) two concepts here. One is a concept about modeling, i.e. about how we think or how we help ourselves to think. The other concept is how we make a description of something we actually observe, as opposed to what we observe in our mental modeling. That quarks “fit the data extremely well” says that the mental model is useful, even reliable for continuing to think about particles. However, it is not a 'given' that the quark model actually describes reality: that which can be observed.

Since concepts are our only way of understanding anything, model we must. But not all useful models are accurate reflections of reality and we keep rediscovering that truth. If people are irritated, it may be that science (physics, physicists) have not made this distinction clear enough, even to themselves. Indeed, failure to make that distinction, mentally or publicly, may be a large part of the “progress problem”.

Saying that a model makes accurate predictions for what we observe is the only way to give meaning to your phrase that it is an "accurate reflection of reality." Maybe one day we'll find a better explanation, but that will not make the quark model wrong, it will merely mean that it's an approximation to something even more accurate.

How do you think nuclear fission and fusion would work if there were no gauge bosons for the weak interaction and no quarks? You may have wanted to say that in the limits in which current technologies work, we can use simplified approximations to the standard model, but if so, you did not express yourself very well. There's no reason future technologies will not exploit what we have learned about the SM at some point.

Sabine,When we find that our skin is wet we can think about why that may be and come up with a number of answers. We can think it might be rain, it might be sweat, or it might be someone pissing on us. Depending on exactly how we observe we can accidentally (unconsciously) or intentionally (built in bias) exclude some factors and include others arbitrarily. Said slightly differently, it depends on where you look as to what you will see. An explanation is not always the explanation. Nothing wrong with that but it means implicitly that not all descriptions are equal.

The current quark model fits the current facts, but it does not exclude a better, even very different explanation. You seem to imply that an improvement will only yield an increased accuracy but, historically, many improvements required very different conceptual models from the original. In the case of quarks, some theoretical improvements wouldn’t make the current model wrong, just grossly inept as a description. I/We don’t know how it will turn out in this particular case, but we do have a fair bit of science history rewriting to look at to see what has gone wrong in people’s thinking. That is where the error always lies, not in the experiment, not in the model, not in the data, but in the mind.

I have long maintained that one of science’s greatest failings is a refusal to examine closely how it has gone wrong in the past. Is science too embarrassed to do that? I do think that such an examination could lead to many more discoveries and advances. Mathematics, modeling techniques, concepts, experiments and so forth, not to mention all the other branches of science, could all benefit from such reexaminations.

What makes you think that the scientific establishment can self-correct? History teaches us that there is a common pattern in the evolution of establishments: They start as a fresh, rebellious alternative to a decadent establishment, gradually degenerate - morally and functionally - finally becoming such an establishment.

For me, the morality issue is far more important than productivity; Who cares if physicists are wrong regarding the temperature at the big bang. But there is an unwritten contract between the taxpayers and the scientists: We shall pay you, and in return, you will cure our diseases, invent clean energy sources etc. Now, how many scientists can look, not only at the body of their own work, but on that of their professors, and their professor's professors, and genuinely argue that the contract has not been breached?

With today's rich private sector, any research with even the slightest chances of success can find funding. And, as Peter Shor suggests, if one is sufficiently obsesses with pattern in integers, he can lock himself in an attic at his own expense (this will also filter out most theoreticians, who are doing research for all the wrong reasons).

The Multiverse Theory is just pure intellectual laziness, like theorizing that gods throw lightning bolts. It is also untestable and therefore outside the realm of science. The breakthrough will come when somebody actually tackles the hard math to explain why the physical constants for ONE universe are what they are.

This post has produced some interesting discussion (among the usual chaff such as this comment), more than I expected. The comments which I personally found most interesting were by Count Iblis, Mitchell, Peter Shor, and Reimond; and of course Dr. Sabine Hossenfelder. (There were probably other good ones which I didn't understand as well.) Unfortunately, only the latter seems to have a blog with a donations button where I can show my appreciation.

You are contradicting yourself. A model that yields the same predictions as another one up to a certain precision will not be very different from the other model. To say is another way: Quarks will remain a good model of reality, regardless of what else we will find in the future.

"I think you are right in saying that mistakes may have been made long ago and also that quite possibly crucial insights have gotten buried somewhere in the literature. However, the experimental situation in physics is entirely different than in the life sciences (I actually go on about this in my book, in case you read this). The big issue with experiments in the life sciences is the enormous number of environmental parameters that can influence the outcome of an experiment, plus the difficulty of reproducing initial conditions (as with cell-lines and antibodies etc)."

Well I suspect every science has the potential to degrade in different ways - both on the experimental and theoretical sides! Also, the issue of cell line corruption was nothing really to do with environmental parameters, and I seem to remember, some researchers continued, knowing that their cells were not of the right type.

I suspect large scientific collaborations that work with seriously expensive equipment. I think 'political' forces may play a huge role - imagine working at CERN and wishing to publish a paper suggesting the the 'Higgs' was actually a glitch!. Even as a post-doc, working with vastly simpler equipment, I encountered the pressure to ignore equipment faults. I suppose I also suspect detectors that are designed specifically to detect a particle predicted by theory. Others can't even check the raw data, because it has to be filtered on the fly by the detectors! The old bubble chambers were much better because you could actually see the particle tracks bending in the magnetic field - but I realise that particles with a half-life of 10^(-25) second, won't show up that way!

I definitely want to read your book - I hope it is coming out in Kindle format soon.

@ Peter Shor:Like you, I'd lay the blame on the poor quality of science management we have, not the scientists. The problem is the evident risk-averse strategy being pursued, squashing innovation, combined with unwillingness to take an appropriate amount of responsibility the decision-making process on the direction of research. The solution is to replace some of the present set of bureaucrats with people (such as venture capitalists) who have the experience and temperament to manage high-risk, high-reward endeavors (which is exactly what science is). Doing bootleg research may be the best strategy for individual scientists to pursue innovation given the current climate, but we need to treat the root of the problem, which is the current climate preventing innovation.

I must agree with "I have long maintained that one of science’s greatest failings is a refusal to examine closely how it has gone wrong in the past. ". So I say - the universe has always been much bigger than we thought. Learn from history.

I think a lot of the issue is the competition and the use of publications (and even citations) over other factors. Competition is suppose to be good, but when it is competition over grants/positions instead of accurately describing reality the incentives really break down.

A lot of theorists try for 3+ papers a year which is just not possible if you are trying to do something difficult/novel. And the best way to get cited is to do something similar to what other people are doing since they are unlikely to change what they are doing just because of your paper.

We experimentalists have it a bit better. There is data that needs to be published and we will often decide to do it in one large publication with lots of results rather than many smaller publications with fewer results. There is bad behavior here also though, since PRL publications are 'better' than PRD/AHEP/JHEP/PLB/EPJC/etc and sometimes universities and funding agencies have bizarre and distorting requirements.

They came up with the idea of atoms in ancient Greece. But, the atoms of that time are fundamentally different from the atoms of today in almost all respects. Yes, today’s concept is more precise, but that is only because there was a vitally necessary change in perception that allowed a different type of investigation using a foreign-to-the-old-Greeks set of conceptions. It wasn’t that the Greeks of old mistakenly rejected today’s concepts, they simply had no way to think like we now do. That difference was not a matter of precision, even though the result was more precision.

While quantum mechanics was born in part out of gaps and unexplainable phenomena in the data and observations previously being used, finding a way to deal with those gaps nevertheless required a completely different way of seeing things in order to become useful for further investigation and advances in understanding. Of course there are connections between classical and quantum ideas. We are still living in the same universe as they were (or so we assume) and therefore, in general terms, we are dealing with the same phenomena. But the difference we have in our understanding now is not simply the result of getting stronger prescription eyeglasses. To stretch the metaphor, we had to be fitted with lenses that transmitted ultraviolet light to our brains and flooded us with new information. Then we had to learn to how to deal with that. More precise (smaller wavelengths)? Yes? Simple extension of what was done before? How could it be? Or, if you think it was a simple extension, can you provide an example of what you consider a huge, paradigm-changing, consciousness-changing leap?

So, what label do you use for radical changes in paradigms? It’s not quite 100 years since we discovered what we now think of as the universe, our previous conception having been limited to the Milky Way. That was a mind blowing discovery. Blown away we were (those who were able to understand the significance of the discovery) to understand how much larger the universe was than the already huge (by our previous reckoning) Milky Way. Some minds may even have snapped and broken trying to take in that change in perspective. What should we call that type of transition in understanding/knowledge? How do we label that experience?

I am not trying to be argumentative. I really don’t know which terms and concepts you use in such situations to mark them as significantly different from what we had before. That’s important because your blog is one of the few places where serious wide-open discussion of these issues is occurring among amateurs and professionals alike. So, if you are not understanding the dynamic I am pointing at, it is quite possible others may not understand what I am saying either. But that doesn’t make the questions less important. I think that it will be useful if we all understand the differences in the terminology we need to use in order to paint bright lines that separate plodding but real progress from real breakthroughs (a horribly abused word these days).

I have great interest in, but no real knowledge of physics (beyond high school). What I find disturbing however, is that physics practitioners seem to avoid off the beaten path or seemingly ridiculous areas of exploration. I think I understand, they need to keep their jobs... Having said that and read your article I think there are a couple of places to look for new stuff. Again, please don't laugh!

I was fascinated to see a performer/magician Guy Bavli move things with apparently nothing but his "mind". Specifically, he was on the show Stan Lee's Super Humans (you can see on youtube). There were no wires, magnets, other setup and viewed/filmed by skeptics. He moved stuff with his mind. I know the first reaction is that it is simply a clever trick. What if it is not? I doubt anyone set up an actual scientific experiment to understand the process by which he performs these stunts. If it is real, I doubt there is anything in physics that can explain it. Maybe, that's a place to explore? Is the lack of progress in physics desperate enough to give it a serious look?

My take is that if such a person as Guy Bavli does not submit to a scientific look at his/her capabilities than you know what's happening, a clever trick. But, if there is no resistance to such a study, it may be a path to some discovery. It would not cost a lot in time or equipment, but I wonder whether it would cost a career?

I am here again for three reasons: 1) I like your argumentation; 2) You write: Help. Please! 3) Sabine's "blog is one of the few places where serious wide-open discussion of these issues is occurring among amateurs and professionals alike."; indeed.

My understanding (I hope, deep enough) of your argumentation differs from that by Sabine. One has to work personally and really intensively on a paradigm change in science in order to feel your trouble with the present situation in physics (and in science in general). A paradigm change is never a smooth transition from an "Old" to something "New". It is always a dramatic, abrupt change of our point of view upon the fundamental problems of our (mental) life. Therefore I treat a paradigm change as "a jump process" (because also a series of cosmic quantum jumps was - and still is- the true motor of the evolution of life on Earth; more, if you wish, on another platform).

The recent answer by Sabine to you shows that she is still not ready to change her paradigm of science. She believes that: "A model that yields the same predictions as another one up to a certain precision will not be very different from the other model. To say is another way: Quarks will remain a good model of reality, regardless of what else we will find in the future." I am sure, you cannot follow her (as I also cannot do). I am sure, the Standard Model will be radically "modernized" in any next, commonly accepted description of Nature.

I wonder if it would be more effective to cease funding some large program (like LHC) and use it for "Gap year" funding for Post Docs to sit around, hang out, and think for a year. No specific programs, no work hours, no guidance or expectations. Just hang out for a year and try to think original thoughts.

Certainly most of the money would be wasted, but it is guaranteed to LL be wasted with these same people sorting LHC data looking for particles that aren't there.

I guess the post docs would first have to be trained how to think original thoughts.

In effect you suggest that what we need is a fundamental rethinking of how we interpret the math that we think we know describes the events we observe. You appear to suggest the answers may be there but we lack the insight to discern the correct method.

@Peter Shor, @Sabine Hossenfelder, you are touching at the key problem: the lack of creativity. But I feel (maybe I am wrong) like humans are most creative at a younger age than that which 99% of them get tenured nowadays. If we want to really flourish creativity we need to empower the younger researchers to follow their crazy ideas, turn the system a lot more risk-tolerant for them. Maybe create something like 4-year grants with no strings attached (something like a unsupervised PhD?) for young researchers who have shown to be more intelligent than average and hard working. Allow them to work in fancy ideas and areas of their liking and not in the ideas/areas of their adviser(s)...

A personal anecdote: once upon a time, I was an undergraduate physics student in one of the top universities of my country (Brazil) and I vividly remember something that disturbs me till today and may have been a direct reason for me dropping out (I was also depressed). One of the professors had an alternative theory that contradicted Relativity. That was motive for gossip all the time specially among the faculty, reaching a point where some other faculty members were exposing his participation in a certain "drug/spiritual cult" famous in our country.

What disturbes me the most was a debate arranged between the alternative theory professor with another professor from a close by university, a specialist in General Relativity. The strongest arguments against his theory were in the line of "Because Dirac's Equation..." or because Relativity has been tested in thousands of different experiments etc...

I really had the impression that the opposing professor didn't even spend more than a couple of hours trying to understand the alternative theory to create counter-arguments for it. And that was for a theory of a tenured professor in a top 3 Physics department in Latin America... Yes, a priori there is still a absurdly high chance that his theory is wrong, but come on, shouldn't it be properly evaluated? Shouldn't some one come along and flesh out some experiment where current theories predict X and his theory predicts Y and hopefully doesn't cost a lot money?

As a student, imagine if one of MY crazy ideas turned out to feel promising, what would I have to do to have if checked seriously instead of simply getting side-handed for not following orthodox theories?

Another suggestion: we need desperately to also fund reviewers as a proper academic path?! People that would work hard to try to understand other people theories (that aren't in the fringes of their current research), and specially fund reviewers that would try to reproduce experiments? As long reproducing experiments have low academic value we will keep this reproducibility crise...

"I was fascinated to see a performer/magician Guy Bavli move things with apparently nothing but his "mind". Specifically, he was on the show Stan Lee's Super Humans (you can see on youtube). There were no wires, magnets, other setup and viewed/filmed by skeptics. He moved stuff with his mind. I know the first reaction is that it is simply a clever trick. What if it is not? I doubt anyone set up an actual scientific experiment to understand the process by which he performs these stunts. If it is real, I doubt there is anything in physics that can explain it. Maybe, that's a place to explore? Is the lack of progress in physics desperate enough to give it a serious look?"

I have to say, I think a more careful study of paranormal phenomena (and various other phenomena of consciousness) might yield dividends. There is a scientist called Dean Radin, who ran a double slit experiment and asked experienced meditators to try to shift the fringes!

The 19th century was a great time to be an explorer. By the 20th century, it was getting tough, because the remmaining unexplored regions - like the poles - were just barely within reach of current technology. Today, would-be explorers talk about other planets, without any realistic hope of getting there.

There are researchers calling themselves "exobiologists" who will probably never see any actual exobiology. Billions of dollars have been spent on probes to Mars; like the LHC, they're technically impressive but unable to answer the big questions.

Likewise, today isn't the best time to be a particle physicist, if the logical next steps require energy and technology we're not going to have anytime soon. Because of the constraints on experiments, the theoreticians have run off into the distance, untethered. A convention of string theorists is probably about as much fun as a convention of exobiologists - hey, let's skip the session tonight and just go to the bar...

My own, completely non-professional view is that we need to look in some very different directions - which mainstream (i.e. professionally employed) physicists have so far deemed unacceptable. But enough on that.

@Lying sweetly, "So, what label do you use for radical changes in paradigms?"Empirical falsification. Physical chirality (baryogenesis and Sakharov criteria) is irremediably ugly math. Theory arrogantly excludes the exact empirical universe, then fails to model it.

Euclid cannot accurately map the Earth. The cure, rejected for 2000 years, violates Euclid. Geometric chiral divergence is trivially calculated. Chemistry builds to extreme spec. The falsifying experiment is performed and published - for another reason, with an inappropriate molecule.

One day of analytical chemistry can heal physics. Look, for nothing other than the ugly answer will succeed...and it isn’t contained within physics.

Sabine wrote: I have spelled out many times very clearly what theoretical physicists should do differently. It’s just that they don’t like my answer.

I've seen many of the suggestions you spell out in your book from other scientists in other fields. I've also seen the same suggestions discussed in the so-called soft science fields. For now, all I can suggest is that change will take time. Of course it would be nice if things don't get worse before they get better.

Sabine wrote: If I inform the public that those architects spent 40 years building houses that all fell to pieces, why is it my task to come up with a better way to build houses?

But like you said, you have suggested better ways to do science. I would argue that partly because of Einstein and Star Trek, people feel optimistic, amazed, and a bit afraid, of the potential power of theoretical physics. Even if there is stagnation, people still feel hopeful about breakthroughs in, say, batteries and fusion power.

Sabine wrote: for most of these two-thousand years people had other things to do than contemplating the structure of elementary matter. Like, for example, how to build houses that don’t collapse on you.

We might yet get distracted by "other things to do," for example, how to stop ourselves from destroying the house we live in - Earth. If we manage not to mess things up for ourselves and the planet, the worst that can be said about stagnation in theoretical physics is that we wasted a relatively small amount of our total resources. If you look at the past two-thousand years, there’s plenty of evidence for the greatness and stupidity of the human animal.

There is historical precedence for inertia in the scientific community, and it is "normal." Resistance to new ideas, self-doubt and self-correction, and outright suppression has been normal. Consider Nicolas Steno (geology), Charles Darwin (evolution), and Alfred Wegener (continental drift). Even if it's true that we have unprecedented stagnation and self-dealing among theoretical physicists, is there any reason to believe we won't eventually get on track?

I appreciate how frustrating it is for someone in their own field to see waste from the inside. Waste can be seen everywhere, even in non-scientific fields. My goodness, the amount of waste in the world, just in terms of poverty, corruption, violence and war, is staggering. Wouldn't it be wonderful if waste in theoretical physics was the worst problem the world was facing? I'm not dismissing the issue; I'm just putting it in perspective. Is stagnation in theoretical physics among the Top Ten worst problems?

Someone might say, "No, of course it isn't the worst problem in the world; you have misunderstood or mischaracterized the article." To that I would point to the dramatic tone of the article, e.g. "it's worse than a crisis, there's no awakening, no self-reflection, blathering, it's unprecedented, they won't listen to me, nothing will stop them." Sabine seems to be as frustrated with theoretical physicists as Eisenhower was about the military-industrial complex, so I think it's worth asking for her Big Picture perspective. Likewise, I’d ask if she wants to continue her career in theoretical physics and fight the good fight from the inside, or leave a profession that’s largely stuck in a rat race.

Dr. Strangelove or: How I Learned to Stop Worrying and Love Stagnation.

"I was fascinated to see a performer/magician Guy Bavli move things with apparently nothing but his "mind". Specifically, he was on the show Stan Lee's Super Humans (you can see on youtube). There were no wires, magnets, other setup and viewed/filmed by skeptics. He moved stuff with his mind. I know the first reaction is that it is simply a clever trick. What if it is not? I doubt anyone set up an actual scientific experiment to understand the process by which he performs these stunts. If it is real, I doubt there is anything in physics that can explain it. Maybe, that's a place to explore? Is the lack of progress in physics desperate enough to give it a serious look?

My take is that if such a person as Guy Bavli does not submit to a scientific look at his/her capabilities than you know what's happening, a clever trick."

See https://skeptics.stackexchange.com/questions/12346/can-guy-bavli-move-objects-with-his-mind/12347#12347 for an argument why Guy Bavli in all likelihood used stage magic.

I think it might be an example of the 80-20 rule, ie 80% of the useful. Work is done by 20% of the people. So when you 10x the physics population 2% of the people do 80% of the work. Today probably 0.2% do 80% of the (useful) work. Adding more people fills up mostly the lower tier universities where not much durable, long-lasting work gets done.

Perhaps the relevant question is why was physics so successfully institutionalized in the last half century or so? Institutionalized thinkers breed Catechisms and String Theory, as "... there can never be any real discrepancy between faith and reason." This process was not spontaneous, but heavily marshaled and funded.

I think that a good part of the answer has to do with importance of physics for weaponry and maintenance of the current pecking order. No self-respecting state wants some loner inventing a zap gun in the garage, or cold fusion for that matter (it's funny how both would have the same outcome.)

The unpredictability of real scientific discovery is the most scary thing for the prominent ... peckers, so neutering the science through institutions is a reasonable startegy and sound investment.

As far as I understand the main underlying assumptions in your argument is that science funding and the sentiment in science community as a whole prevent new revolutionary ideas.

I disagree on multiple counts.

Firstly, you can't direct the field as a whole, nor its funding in theoretical physics towards unknown, revolutionary and unexpected productively. You may get periods of free association, and crazy ideas for their own sake, but not revolution. More people thinking more time does not solve problems when the problem is lack of insight.

Heavily funded research towards unknown can work in engineering (Xerox PARC etc.) where the idea is to build from known pieces something new. In physics the problem is more analytical: looking at the thing and seeing what the pieces are. You can't just put money and table and make a group of physicists that step outside of their thinking.

Secondly, the general atmosphere is not hindering theoretical physicists at all if they have idea worth of pursuing. I claim that all brilliant physicists of today can find a easy teaching job that brings food to the table and leaves time to think, and do original research. What they don't get is prestige or high potions before they produce a breakthrough. As it should be. There is choose and it's open to every smart physicist. But they have to choose. They can't be both recognized and the fringe at the same time.

Newton was Newton's was undistinguished as a Cambridge student who made his work in private at his home in Woolsthorpe. Einstein worked in patent office.

You can see plenty of people pursuing their own ideas. Just few random examples from the top of my mind. Cohl Furey and her octonions. Robert B. Laughlin (Nobel Prize in Physics – 1998) had emergent relativity. Twistor theory from Roger Penrose, Causal dynamical triangulation. Almost all physics department have at least one brilliant physicist working silently on their pet approach. It may have to do with magnetic monopoles. information theory or something else, but they exist.

Many of them have published articles of in. There are thousands already explored attempts in the arXiv.

Finally, I believe that when someone comes up with idea worth of truly pursuing, enough pole notice it that it can be explored forward. Eventually it wins over. Physics may be in a jam, but it's not something that can be solved with metaheuristics or money.

Lying wrote (to Sabine): You seem to imply that an improvement will only yield an increased accuracy but, historically, many improvements required very different conceptual models from the original.

Sabine wrote (to Lying): You are contradicting yourself. A model that yields the same predictions as another one up to a certain precision will not be very different from the other model.

I see this as a semantic issue. I understand the points on both sides and I don't think Lying is contradicting herself. There's nothing wrong with pointing out differences between the concepts underlying models. If the conceptual change is big enough, sometimes we call it a paradigm shift. Ah, another metaphor.

The model of a flat Earth works fine up to a certain point: point taken. The concept of a spherical earth is very different, even if the two models "yield the same predictions" in certain circumstances.

It's common to hear that Einstein overturned Newton. Some sticklers point out that Newton's laws are valid approximations in many circumstances, which I think unreasonably misinterprets what is meant by "overturned."

In every discussion where I've said it was a semantic issue, in contrast to a substantive issue, I've been told I was wrong. Despite my experience, I'm sure people sometimes agree that disagreements come down to semantics. For whatever it's worth, that's my two cents on the discussion between you and Sabine.

Laszlo wrote: My take is that if such a person as Guy Bavli does not submit to a scientific look at his/her capabilities than you know what's happening, a clever trick.

Ask yourself how likely it is that Bavli will ever submit himself to genuine scientific testing. You're correct that it wouldn't cost much in time or equipment. And even if he did, it wouldn't necessarily harm his career as a professional magician. In general, people understand that magicians use tricks.

Look at the long list of cash prizes that would be awarded to anyone who can demonstrate "paranormal abilities."

Of course, if Bavli could demonstrate such abilities, he would gain a lot more than cash prizes. The global scientific community would fall over themselves coming up with new hypotheses to explain it, and Bavli would become the most famous human in history. If The Beatles were more popular than Jesus, Bavli would be more popular than The Beatles.

Best of all, for Sabine at least, if Bavli could demonstrate paranormal abilities, all the string theorists would flock to Bavli. A hypothesis in the hand is worth two in the bush.

Totally agree with your suggestion! But I think the progress in Quantum information and computation is quite rapid, right? Or do you think despite the progress the foundational aspects and questions of QM is still the same?

Good arguments as always. Science is like a good wine. Sometimes you have to let it ferment for a while until the time is right.

It is obvious that science is currently looking for the answers in all the wrong places. But that is okay. It serves to eliminate the wrong ideas.

One day soon (within the next five years), the ‘dark matter’ problem and many others like it will be solved. I predict, however, the answers will not come from the establishment, but from some youtuber. Of course, it will not be readily accepted by the establishment, but nonetheless the new theory will prevail.

While I quite agree with your general view of the problems besetting modern science, I cannot concur with your causal analysis or proposed solutions. At root, the current state of affairs is a direct consequence of the fact that, over the last century, the critical role of empiricism in science has been increasingly supplanted by mathematical modeling.

It is wrong to assert, as you did to Lying sweetly regarding quarks,

Saying that a model makes accurate predictions for what we observe is the only way to give meaning to your phrase that it is an "accurate reflection of reality." Maybe one day we'll find a better explanation, but that will not make the quark model wrong...

You are claiming that a mathematical model that "works" somehow overrides the physics we actually observe. In this brave new "science" negative empirical evidence has no value. Nature may exhibit no need of quarks but if the model requires them, they must be there? That is turning science on its head.

Quarks are not a good model of reality for the simple and straightforward reason that quarks do not exist in physical reality. Models that can mimic observations by freely parameterizing, are at least as old as Ptolemy. That those free parameters have any correlate in physical reality can only be determined by empiricism. That a model "works" does not verify, justify, or provide evidence for, the physical existence of things that cannot otherwise be observed to exist.

That this model-centric approach is the operative paradigm in modern academic science is the fundamental reason that the two standard models of physics bear no resemblance to physical reality. Rather, they describe a reality composed of entities and events that do not, in fact, exist in observed physical reality.

Theoretical physics is not simply stagnant, it is at a dead-end of its own construction. Nothing will change until our theoretical models are built firmly on the basis of empirical realiity. Idle mathematical conjectures cannot be the basis of science. That path contains many worlds, but none that resemble the observed reality that is the only proper subject of science.

I think you are overreacting. The more we probe nature, the levels of comlpexity rise, new pathways open, snd it takes a long time to follow them all. The more we discover, the harder it is to come with new ideas, not to mention, all the problems scientist face today to do research. I think your argument about time is flawed, the fact that it occurs is manifold, and I don't think scientist are inherently less efficient, the science apparatus may be, but not because scientist refuse to follow new leads or stop others from doing so. As a matter of fact, I think "science administrators" and pleople who are not experts are running the show, and they specialize in rowing backwards. We need new ideas, that's for sure, and just as Don Lincoln said ¿Do you have a better approach? Besides, what happens if something like SUSY turns out to be right? All your criticism here becomes irrelevant.

I have no idea what your recent comment has to do with quarks. All I was saying is that the quark model is a good model because it yields accurate predictions, and that it will remain a good model even if we eventually find one that yields even more accurate predictions. That we cannot observe quarks in isolation is entirely irrelevant.

You ask "what label do you use for radical changes in paradigms". Well, I guess I'd call it a paradigm change, as everyone else does.

Yes, the structure of theories can change. I don't think I said anything to the contrary. I simply pointed out that the idea there must be something wrong with the quark model because we cannot observe quarks in isolation makes no sense. It's a good model and it will remain a good model, even if we learn in the future that it can be derived from a more fundamental theory.

"I simply pointed out that the idea there must be something wrong with the quark model because we cannot observe quarks in isolation makes no sense. It's a good model and it will remain a good model, even if we learn in the future that it can be derived from a more fundamental theory."

I cannot agree with Sabine in that point, in no way.

Standard model says that up, charm, and top quarks all have fractional electric charge of +2/3, while down, strange, and bottom all have a charge of -1/3. It is a senseless idea to divide a single quantum (of charge in that case), like it would be a wrong model including an idea of light based on half photons (for example). If quantization belongs to reality, than absolute, everywhere, and any time. No model ignoring the very idea of quantum can be thought of as "a good model".

Your comments are exceedingly uninformed and I will not approve more of them. You clearly have very little idea how the standard model or quantization works. Of course you can give quarks a fractional charge and, as I have noted multiple times, this model works extremely well, so your complaints about it are what I call "aesthetic itches" in my book. Which, btw, I recommend you read. Or if you read it, read it again, because clearly you didn't get it.

Hi Sabine,I love your work. I am far more optimistic in the sense that as we expand in space, we will find disproofs of the actual incorrect assumptions that are leading us up the garden path of wrong predictions.There are already signs with many anomalies being explained with tentative physics that are currently being rejected by peer review. Also rejected in principle by the mainstream. This is due to the very financial incentives that are leading physics astray. It is nice to know to be right where all the scientists have been wrong in the near past, but unfortunately, it is much more important to be respected and funded, than to be right but disrespected. I personally have discussed a Quantum Gravity revelation with a theoretical physicist who is now destitute and homeless, although she almost certainly unlocked where Quantum Gravity is going wrong.

I see little hope, because each of the revelations I have seen on the sidelines in pre-publishing platforms have little chance of even being seen by the eyes that need to see them. Even you, Sabine, are likely to ignore such revelations as being a fringe pet theory and unlikely to read them where they are or pass any comments that give summary of them. There are too many alternative theories as well, and your approach not to look at any comments that explain an alternative is a very common approach, and realistic. How is one supposed to find the needle of a right alternative physics in a haystack of pseudoscience?

The peer review is not working in this respect, but it is supposed to. It is supposed to weed out obviously wrong theories and pass only good science. Due to the system as you describe it, there is a haystack of papers here without even a needle of correct predictions to find of late.

There is a real need to favour theories with utility and coherence, whether they are peer reviewed or not - Or to overhaul the peer review system with these broad concepts to the forefront.

It is time to wake up when the “blathering about naturalness and multiverses …” already can be used to ridicule the Commander in Chief.The standard model and GR each are working like a charm, we just need to find the missing link.Consistency is a precious asset and a guidance.

If real advances are achieved by solving hard math problems, and if the disconnect between GR and QM is the fundamental problem, then wouldn’t we want to focus on developing a mathematical model whereby GR can be described/derived in terms of probabilities?

… 1) Science forbids violating observation. Faith demands it.… 2) To criticize is to volunteer.… 3) Dr. Awkward does it the other way. Quality Control versus Quality Assurance, absence of failure is success,… 4) There may not be a pony.

https://www.youtube.com/watch?v=ejODUWR2yqM… So it can't be done, so what? LOOK

Tim Maudlin's article "The Defeat of Reason" is very relevant here: http://bostonreview.net/science-nature-philosophy-religion/tim-maudlin-defeat-reason

When scientists abandon the strict discipline of reason, then what else can we expect but confusion and stagnation?

But these problems aren't restricted to physics, the University system itself is sick; its legitimacy is in question except for job-related training. Future progress in fundamentals will probably look a lot like past progress: it will come not from institutionally recognized scholars but from independent (and often non-credentialed) researchers.

IMO the problem is broader. Contemporary scientists have abandoned the basic rules for making good science. They don't use definitions, therefore anything can be said and it can't be ridiculed or doubted. They have abandoned the old rules for scientific works: 1) at the beginning of his work the authors describes, defines the field he has added something to and shows that his work contains essentially new knowledge, not known before; 2) further the author describes what is known, and what isn't and defines the problem he proposes the solution for; by the way author cites known acceptable definitions he is using and creates the new ones necessary for the solution he proposes; 3) author describes how his new solution works, supplies the facts and proofs for his solution and makes predictions which will prove his understanding or position; 4) in conclusion author shows in which way his proposal is better than the known ones. Imants Vilks

When you have missed your freeway offramp (an answer heading towards the truth), no matter how much further down the road you go with your stubborn inability to admit you are lost, you will still be going the wrong direction no matter how much publicity you hire to claim othrwise. Sometimes, it is far better to eat some crow, turn the car around and carefully examine where you went off track.

The greatest obstacle to science is not lack of funding, it is hubris. Until you get over it, the fear of being seen as 'wrong' greatly eclipses your ability to correct course and repenser.

The big question is no longer 'Are we lost?', the question is, 'How lost are we?'.

How far do we need to back the damn car up until we are once again on track?

Dear UnKnown….Definitions require assumptions about the field you attempt to describe which in turn requires a group of conscious or unconscious assumptions/axioms that may or may not apply to the objects under consideration.

For example Gravity is treated as a force in some cases. General relativity treats it as a property of space. Force or Property ??? Definition? Assumption? Axiom? Or something else entirely? Fact is if we could answer the question "Lost in Math" would not have needed to be written.

Great discussion. Could it be that we have different dimensionss, which we understand one perspective of it and can’t translate one to the other unless we have a fudge factor. What if for instance space-time continuum is in one dimension, mass-energy in other and Electromagnetism and vibration on the third one. What if we don’t have a right understanding of how these dimensions correlate since we are part of all three.

Maybe it is a sort of "Zeitgeist". There are same tendencies in almost all branches of society:

enforced conformity, adaption, radicalisation against outsiders, lack of thinking - and partiular in science the overwhelming faith in the "wisdom of math", not aware that a consistent mathematical theory can, but haven't to describe reality.

I'm curious to know how all of you see this issue from a Big Picture perspective.

For the sake of discussion, let's accept the worst-case scenario that theoretical physicists are currently stuck in a self-serving rut and have no clue. Time, money and brains are being wasted. Let's further assume there will be little or no improvement over the next several decades, and when we reach mid-century, we won't be any closer to finding a GUT or a TOE.

First, does this problem belong in the Top Ten, or even the Top Hundred problems humans are facing in the world?

Second, is there any reason to think that the scientific community won't eventually take steps to fix this problem?

A corollary question:

Let's assume an even worse worst-case scenario. Let's suppose that humans are reaching a limit in our capacity to understand and model the nature of matter and energy. Let's suppose that no matter what we do, we'll remain clueless. In other words, reality will forever be shadows on the wall of Plato's cave, and we will forever be blind people feeling an elephant. Our only consolation is that we'll develop some additional technological and biological innovations.

Would such a scenario cause a crisis in the scientific community? Would we graciously accept our limitations and marvel at our successes, or would we see it as a tragic failure?

I enjoy my life, but I'm also incurably curious about humanity 200 years from now. If I could put myself in suspension for 200 years, I would do it today without any hesitation. I'd want to see how it turns out, even though I know it might turn out badly. I think the next 200 years will make or break the human race.

Few arguments really need more than, say, 5 to 10 sentences to be presented. Somebody says "Perhaps this stagnation is a consequence of our inability to surpass the limits posed by our ape brains". Another says : "Revolutions in physics never stem out of the established academic guilds". These are simple, concrete, and robust ideas about what might be wrong, which do not require many words to convey the meaning their authors wish to convey. Therefor, I do not see the reason for some page-long replies, which make them incomprehensible or even boring to read. A word- or sentence-limit would be most helpful. Less may well, sometimes, be more, indeed !

I actually pray for budget cuts in HEP for the very reasons you outlined, not because I am cynical of science (exactly the opposite) but because I want it for succeed. Money for results, it's that simple. The current administration doesn't know or care about the outcomes, the ideas just look cool. When the financial reckonimg arrives, hard decisions will have to be made and armchair philosophy in the form of multiverse will end. It's sad because a lot of good science can be done with few resources (James Van Allen had a great talk on this), we just don't know what good science is anymore when we talk about not requiring falsifiable verification.

Dear Sabine, you write:"I have spelled out many times very clearly what theoretical physicists should do differently. It’s just that they don’t like my answer. They should stop trying to solve problems that don’t exist."

Can you give an example please of what they should be working on. Thanks.

You quote the very paragraph in which I answer the question. How about you read the next sentence? Focus on mathematically well-defined problems. I have given examples of this already in the comments above, as well as in my book and in literally every single talk that I have given.

Sabine,I guess qsa (and others) means some concrete examples of research avenues which, according to you, should be more promising than the currently popular ones. Your suggestions in the paragraph you mention ("stop trying to solve problems that don’t exist ... Focus on mathematically well-defined problems" etc) are sort of platitudes, that's why people keep asking. Also, who exactly stops you (or your colleagues, PhDs, postdocs) from pursuing these alternative avenues?PS: example with architects is silly. Nobody would ask you to give technical advice to architects, because you are not one! But you are a physicist criticizing other physicists, so we have a right to ask you what you concretely suggest to do.An appropriate example is this: take an opposition politician who criticizes the measures taken by previous government, but does not come up with any concrete suggestions except "stop trying to solve problems that don’t exist ... Focus on economically well-defined problems".Would you vote for him/her? Wouldn't you ask what precisely he/she plans to do?

Scientists have been “hiding in their attics” since Newton retreated to his farm in 1665 and discovered the law of gravity, the laws of motion, calculus and the spectra of light. Heisenberg invented matrix mechanics during his isolation due to hay fever. Perelman solved Poincare conjecture in reclusion at home. Milankovitch developed the Milankovitch cycles under house arrest as a prisoner of war in World War I

I already replied to this question above. Here it goes again: Quantum gravity, Landau Pole, non-perturbative formulation of qft, to name a few.

"example with architects is silly. Nobody would ask you to give technical advice to architects, because you are not one! But you are a physicist criticizing other physicists, so we have a right to ask you what you concretely suggest to do.

You have "right"? You gotta be kidding me. If those people can't figure out what to do, then maybe we shouldn't throw tax-money at them. It's not my task to find them something worthwhile to do. And even so, despite not being my task, I did offer very concrete suggestions. Just to then have people like some opa manfred to ask exactly the same question again after I just answered it.

What this shows to me very clearly is that you are not interested in actually getting an answer from me, you merely want something to complain about.

It's funny, but since I've finished my PhD, I've become less and less interested in any foundational physics question. The simple fact of the matter is, we have so much unexplained phenomena in our current universe with our known theories and that there is so many rich avenues of exploration that don't have many people working on them.

Just in my own area of expertise, GW18017 has given us the first really good detection of kilonova in multiple bands, and yet we barely understand the process and physics behind it. There is a lifetime of research ready to be done there, but only a few people work on it. Pick also tons of other interesting astrophysics phenomena that are full of rich explorations but just not enough money or people. Personally, I would stop researching the foundations and instead focus on understanding the known unexplained phenomena better. From my study of physics, it always seems new physics and ideas arises when analysing known experimental results and trying to interpret the data.

Stagnation of this sort, while undesirable in some ways, is also a rather happy state of affairs. We’ve exhausted large regions of the space of possible discoveries, and our theories are pretty robust given how good we are at navigating the theory space (rendering unconceived alternatives unlikely). We’ve snagged the low hanging fruit at low energies, and what’s left won’t lend itself so easily to discovery.

Several people have pointed out that “outside the box” work on foundational physics is being done, by a fairly wide range of people, in many different settings (including “in the attic”). Not sure if anyone has tried to estimate how much, by type; now looked deeply at where results get published. But it seems clear that, as a fraction of “standard stuff”, it’s very small; certainly there are no “communities”, like those in hep (I’m ignoring crackpot communities, no I don’t want to give any free publicity).

From my own reading, one common (but not universal!) failure of the “alternatives” is to pay too little attention to possible experimental or observational tests. Sometimes it’s so gross as to have done no real work to see what has already been published, by astronomers say.

Sabine,We have been at physics for a very long time and here we are. Much of what we know is solid, but we know it is incomplete. Perhaps there was an early flat-land assumption that now prevents the pieces from fitting together. Perhaps the entire geometry of our physics is nested within a more extensive topology.

By the time you have arduously navigated the educational maze to an understanding of current theory in all its complexity it would be difficult to assess which walls may be figments of early apprehension. But it has been delightfully done.

Our experiments precisely aim incredibly ponderous and complex devices to bring one small facet of reality into frame for a snapshot. Sometimes there is a revelation, but we lack the innocence to declare the theory has no clothes.

As an example of early apprehension, we accept the notion of temporal distinction between events as real and necessary. Perhaps there is a device and an angle of view which would reveal that all events are, in addition, temporally concurrent. Understanding such a paradox would keep some folks busy for a while.

An option could be to get to collaborations on projects that are hard to get off the ground using conventional means. Instead of trying to get grants to hire Ph.D. students and post-docs, you can try to get qualified people who have some spare time left to join forces online, similar to the PolyMath project.

There is a Kindle-version on offer on the US-Amazon site in my browser. I have no idea what's up with the UK page -- you are not the first one to complain about it -- but I am afraid there is nothing I can do. I know that other people have managed to read the Kindle version, even in the UK. I am sure it exists.

opamanfred wrote: An appropriate example is this: take an opposition politician who criticizes the measures taken by previous government, but does not come up with any concrete suggestions except "stop trying to solve problems that don’t exist. Focus on economically well-defined problems".

Funny you should say that when I happen to be reading "5 Easy Theses" by James Stone. He offers "concrete suggestions" for five of the most important public policy issues that are "eminently solvable," while avoiding problems that are "genuinely hard to solve."

I'm guessing the title is a pun on "Six Easy Pieces." I wonder what Feynman would say about the current state of theoretical physics.

It may well be that I have misunderstood your position re quarks, leading to this exchange:

BR: You are claiming that a mathematical model that "works" somehow overrides the physics we actually observe.

SH: I certainly never said anything like that and have no idea why you think I did.

My statement derived from some recent comments of yours that seem to offer unqualified support for the quark model. I took that support to mean that you consider the existence of quarks as physical entities to be factually established. If I am wrong about that and you only consider quarks to be artifacts of a mathematical model that has some utilitarian value, then I apologize and retract the statement.

OTOH, if it is your belief that quarks are real physical entities with fractional charges, then it is exactly such a belief my comment was aimed at. Because of your reply above, it is not obvious to me which of these two positions you hold. Could you please clarify? Thanks.

"My statement derived from some recent comments of yours that seem to offer unqualified support for the quark model. I took that support to mean that you consider the existence of quarks as physical entities to be factually established. If I am wrong about that and you only consider quarks to be artifacts of a mathematical model that has some utilitarian value, then I apologize and retract the statement.

OTOH, if it is your belief that quarks are real physical entities with fractional charges, then it is exactly such a belief my comment was aimed at. Because of your reply above, it is not obvious to me which of these two positions you hold. Could you please clarify? Thanks. "

What you're doing here is called a false dichotomy. I have explained above very clearly what my take is on the quark model and it's neither of the options you try to force on me. To repeat this: The quark model describes our observations exceedingly well. I don't know what it means for something to "exist" and I don't know what "reality" means. If you find out, let me know. Until then, I remain an instrumentalist. A model that works, works, we will use it, and whether some commenter on my blog complains that he doesn't like fractional charges is entirely irrelevant.

I read your book a few months ago and very much enjoyed reading it. Congratulations for putting so much thought into it. I particularly liked your description of Weinbergs office. Perhaps if we all had larger offices we could get more and better work done!

You seem to have fundamentally misunderstood the concept of 'fractional' charge. The 'charge' on an electron is 1.60217662 × 10-19 coulombs in absolute terms and SI units so we're already starting from a position of 'fractional charge' (0.60217662 × 10-19 coulombs). For simplicity particle charges e.g. electron, positron, proton, quarks etc are usually given relative to the electron charge. Thus charge on a proton is +1e, the charge on an up quark +2/3e.

By using the relative values it aids clarity and comprehension.

For example it's far easier to write the up quark charge as +2/3e rather than + 1.0681177466666666666666666666667 x 10-19.

If it makes you feel happier go through the SM equations replacing 'e' with 1.60217662 × 10-19 coulombs wherever it occurs.

The best experiment I did in college was a repeat of the Millikan Oil Drop Experiment. The electron's charge is the smallest charge observed in nature and all other observed charges are multiples of it (as demonstrated by the MOD Experiment). Therefore there is no empirical evidence of a smaller charge, which the quark model assumes.

(I don't have a problem with the quark model myself, but bud rap is pointing out that we have no direct evidence and theories with hidden properties, e.g. the god theory, have the potential for multiple explanations with the correct one being unknown.)

If Fractional Charges don't appeal redefine the unit. It's only a scalar factor in the final equations. You'll be out of step with everyone else but hey whatever makes you happy.

Fractional charges only 'appear' thanks to George Johnstone Stoney FRS (15 February 1826 – 5 July 1911) who defined the charge on the electron as 1e. Had dear old George taken the long view he would undoubtedly have defined the charge on the electron as 3e making the proton charge 3e, the up quark charge 2e etc.

This is true if, and only if, you discount the fact that quarks are not found in the realm of observation (inclusive of instrumentation) and measurement - the realm of science. By that standard, both our particle physics and cosmology theories are just fine - we can simply ignore the problems (of missing and invisible entities and events) while focusing on the ability of the models (with invisible free parameters) to be sculpted into agreement with observed reality. It's the Ptolemaic approach on steroids - peer reviewed, well funded, and impervious to criticism.

However, "the model works" is not the same standard as, "the model accurately describes the nature of physical reality". The question, whether quarks are part of observed physical reality or not, is anything but a false dichotomy. It gets to the heart of the problems of modern science that you, Lee Smolin, Stacy McGrath, Peter Woit, and others are grappling with.

I would suggest to you that this problem you is precisely illuminated by your reluctance to address the question of whether quarks are part of physical reality or only part of a mathematical model. (I know you know the answer.) The inability or unwillingness to clearly distinguish between a model and observed reality is what it means to be lost in math. The clarification of the science/math distinction at the theoretical level is critical to restoring a scientific perspective - to the scientific academy. Instrumentalism is not fundamental to science, empiricism is.

"This is true if, and only if, you discount the fact that quarks are not found in the realm of observation..."

The quark model describes measurements well. I don't know what you mean with quarks "not being found in the realm of observation". This seems like meaningless verbal gymnastics to me.

"I would suggest to you that this problem you is precisely illuminated by your reluctance to address the question of whether quarks are part of physical reality or only part of a mathematical model. (I know you know the answer.) The inability or unwillingness to clearly distinguish between a model and observed reality is what it means to be lost in math. The clarification of the science/math distinction at the theoretical level is critical to restoring a scientific perspective - to the scientific academy. Instrumentalism is not fundamental to science, empiricism is."

In contrary to what you accuse me of, I have been exceedingly clear in expressing myself. I have told you from the very beginning that quarks are a model and that I do not make statements about reality. I don't know what it is. You are the one who insists on doing that, despite the obvious fact that you don't know what reality is either.

Empiricism would return us to the 18th century. I'd rather stay in the 21st.

I find the comment, "the quark model works" to be interesting because it brings into question the need to define what is meant by "works"? The model clearly identifies the number of "elementary particles", i.e. quark combinations, so it represents something, but what? As far as I am aware, it does not predict the masses of these particles, nor the lifetimes, but I could be wrong there. You can never observe an individual quark. The standard model gives a reason why not, but the force field that imposes the effect gives, as far as I am aware, no other observable effect, so it only explains what it was constructed to explain. That does not mean the model is wrong, but it does give skeptics something to work with.

From my own point of view, I find the quark model to be the most satisfactory available, but it is hard to know what it means. For example, one could be dragged into arguing that quarks are one-dimensional or two-dimensional entities, which is why we have the fractional charge. There we have a model that "explains" what we see, but again that is circular because it only explains what it was specifically constructed to explain. Are quarks really any better in detail? (As opposed to Feynman's "partons"?)

Heh. Strict instrumentalists will always be at odds with strict empiricists to the extent the former denies realism while the latter insists on it. But, as Sabine points out, the modern age requires some degree of instrumentalism. Quantum physics can even be taken to deny realism!

"According to membership data from the American Physical Society and the German Physical Society the total number of physicists has increased by a factor of roughly 100 between the years 1900 and 2000.* Most of these physicists do not work in the foundations of physics. But for what publication activity is concerned the various subfields of physics grow at roughly comparable rates. And (leaving aside some bumps and dents around the second world war) the increase in the number of publications as well as in the number of authors is roughly exponential."

Perhaps this has been commented on already in this thread, but if Sabine's numbers are correct (I assume they are.) then might not the exponential growth in the number of physicists be part of the cause of the current stagnation?

Crowd effects are amplified as the crowd gets larger. There are proportionally more physicists writing more papers that repeat and reinforce the same assumptions making it harder and harder to resist herd pressure.

I have the sources for these numbers in my book. It's membership data from the APS and the German Physical Society and numbers taken from a book about physics a century ago. I also collected some references here, though you will have to combine the information. They'll tell you that the number of papers is growing exponentially but that the number of papers per author is remaining constant, so the growth is actually driven by the sheer number of people. Of course that growth will saturate at some point but so far there's no indication for that.

Having sad this, do you have a reference for the assertions you make about the size of groups making social feedback more pronounced? There are arguably problems that come from the size of groups, notably it's the fragmentation of knowledge, which comes from the need of people to cluster in groups of manageable sizes. That is to say, large communities make information sharing much harder, and that plausibly amplifies communication problems such as the shared information bias. But I am not sure what effects you may be talking. Best,

Are you talking about groupthink? I would think that would require a more cohesive group than perhaps physicists are and active suppression of alternative views, which I also doubt exists.

Certainly more physicists mean more people with a need to publish something new and, hence, more bad ideas and wrong predictions but that doesn't account for the absence of good ideas and prediction. Although, I guess, it could be there are good ideas and predictions out there that are getting drowned out by the bad ones.

Most likely we have made as much progress as we are going to make on the big questions on the current scientific foundation and we will need some big new idea to go to the next level. And those sort of ideas don't come from perspiration but from the other 1% (see Edison quote about genius if that makes no sense).

Sabine and Jim Cross have already asked the questions I would have asked about your statement. To that I'll add a couple of comments.

Even if there is some "herd pressure" and a tendency to "repeat and reinforce," would that be enough to prevent the kinds of skepticism and self-correction that the scientific method is known for?

Moreover, isn't it the case that some scientists dream of being the one who discovers a revolutionary new insight that overturns previous paradigms? Horatio Alger wrote rags to riches stories, but don't scientists have even bigger dreams?

One of the mottos of science is that one's beliefs should follow the evidence, in contrast to the religious motto that one's beliefs must remain the same in spite of the evidence, as a test of faith. If the herd isn't following the evidence, some scientists will eventually break from the herd.

"...I do not make statements about reality. I don't know what it is. You are the one who insists on doing that, despite the obvious fact that you don't know what reality is either."

I have to admit that I am perplexed by this remark. Being a theoretical physicist, what is it that your models attempt to capture, if not at minimum, the behavior of objects and events in physical reality? When you say the quark model "calculations accurately describe what we observe" are those observations not of physical reality? It seems peculiar that, a a scientist, you claim to have no concept of a physical reality.

As for my part, I have a perfectly good working definition of physical reality: it is the aggregate of all those things that can be observed and measured. Observation here, being broadly inclusive of both our human senses and their mechanical extensions. Interestingly, this definition is derived directly from the definition of science that was commonly given when I first became interested in the subject 60 odd years ago.

Science, we were told in that era, is the study of those things that can be observed and measured. In light of this conversation, I'm beginning to wonder if you were introduced to science, some 30 years on, with a different definition. That would go some ways in explaining why we appear to be talking past each other.

I have answered this question a few times now. I do not understand why you keep repeating it. We use our models describe observations.

You now want to define reality as all we observe, but if you think about it for a moment you will notice that doesn't make sense because you will then have to define what it means to observe something. Who observes, what does it mean to have observed something? As I explained here, almost all our observations are indirect inferences. So what's real then? Is anything?

Look, none of this discussion is new. Philosophers have been through this endless times. I already told you that I'm an instrumentalist and you can look that up if you don't know what I mean.

Perhaps, people that work in this field should do just that: work. Then may be the foundation of physics would be in a better shape. It seems that people in this field do write popular books, maintain blogs with literary hundreds of comments, do interviews and reviews, travel a lot not always because of research, have families and life outside academia. No wander that the progress is slow in the field. Of course physicists from all subfields do that, but to me its seems that in this particular field it is a lot more. May be some one can check it out.

Hi Sabine. Please do not equate the phrase "foundations of physics" with high energy physics only. There is plenty of new and exciting, and I would argue just as "foundational", advances happening in other sub-fields of physics these days. I write this only after being puzzled by my wife asking me if my field had stagnated. Best Regards, Steve Simon (Theoretical Condensed Matter Physics)

Did you really just criticize me for writing about physics in my free time and for having children? And are you not the same commenter who previously declared my research must be of low quality, because my papers are not an incomprehensible mess of meaningless equations and then refused to sign off their "criticism" with an actual name? Have you learned so little?

I do not equate the foundations of physics with high energy physics. I do not know why you think so. I have explained very clearly in my book what I mean "foundations of physics." High energy physics is part of it.

No, I didn't criticize just you,I criticized many people. You happen to be one of them. Do you disagree that physicists that work on the foundations do more popularization and more outreach than the others?

No, I didn't say your papers must be of low quality because they are not "an incomprehensible mess of meaningless equations". I said that they must be of low quality because they look like an exercise for the graduate student. If I can read any one of them in an hour, and I am not a physicist, how good can they really be.

By the way, you criticize many people. You shouldn't be so jumpy, when you get criticized.

I don't understand! Why do you have to deal with anything (when it comes to me)! I simply expressed an opinion. To repeat: maybe (just may be) if physicists in the foundations worked more and spend less time on other things, the state of affairs would be better. To clarify, by other things I mean popular movies, TV programs and books, blogs and rants, reviews and interviews, a lot of non research traveling. Or if they prefer these things over science, fine, but then less complaining (may be).

Space Time, did you just declare that the quality of something is how much it makes you struggle? Holy cow. You've internalized the whole chauvinism of worth based on middle school rivalries and then you applied it to science.

Sabine, whatever else you must not forget you have a life. The idea that seems to be put forward by some that writing blogs and doing a whole lot of other things is a waste of time is just plain nonsense. I happen to agree that science is not making great advances right now, but I think the reasons for this is simply that everybody is too specialized and too busy getting funding and doing whatever is also needed for that. So, keep up the blog. Remember, anyone criticising you for writing it is also reading it.

Thank you for writing this. I am only an engineer, but used to suspect while in graduate school, that a lot of research was like this.

That said, physicists should not feel depressed, or attempt to jump off tall buildings due to this state of affairs:

1. At least you are spending some of the time educating students. Education is a wonderful contribution to society. Hopefully some of the students would do fruitful things, even other than theoretical physics.

2. You are not spending your time creating things like CDOs (collateralized debt obligations), which sent the world economy into a tailspin a decade ago. Nor are you bombing civilians in the middle east. There are far, far worse things being done in the world than string theory!

3. Maybe things are kind of like in equilibrium for a while. It's like the teenage adolescent who disappears into their room and nothing happens for years. False starts, useless stuff, weird hairdos and clothing have to be tried out. After some years, you (hopefully) suddenly see a responsible adult emerge!

Bernd Ehlert said:A voice from philosophy to "The present phase of stagnation in the foundations of physics is not normal".And if the present phase of stagnation in the foundations of physics is normal?

Kant says:"Up to now it has been assumed that all our cognition must conform to the objects; but all attempts to find out something about them a priori through concepts that would extend our cognition have, on this presupposition, come to nothing. Hence let us once try whether we do not get farther with the problems of metaphysics by assuming that the objects must conform to our cognition, which would agree better with the requested possibility of an a priori cognition of them, which is to establish something about objects before they are given to us. This would be just like the first thoughts of Copernicus, who, when he did not make good progress in the explanation of the celestial motions if he assumed that the entire celestial host revolves around the observer, tried to see if he might not have greater success if he made the observer revolve and left the stars at rest." (Bxvi–xviii)

If being is ultimately not real, then there is no ultimate explanation or knowledge of being in the structures of being.

There is a general pattern of seeking comfort within acknowledged frameworks.

In the technology of computing machinery this is more pronounced, as participants tend to be in a different part of the cognitive spectrum, yet there are striking similarities:

1. A dominant model takes over: while server-client paradigm is a microscopic fraction of possibilities in the computing, it is the entirety of the practice. For many it is literally impossible to think out of it, as they have been conditioned and shaped so in education and practice. This has huge consequences in many aspects use, yet it's even not a topic.

2. It's possible to spend a rewarding lifetime working and elaborating in a small part of this microscopic fraction. There are whole industries around it. New simplified languages that enable lay people to 'program'. Rental machine farms. Data extraction. Bootcamp courses.

Sooner or later the whole ecosystem runs into a wall due to limitations of the original premise, but the solution is invisible from the inside, and most capable of finding it are already inside. Those challenging the original premise are sneered at in various ways.

Regarding the computing arena, I don't see a solution other than some form of pitchforks from the affected villagers. The physics sanctuary is probably much safer.

You now want to define reality as all we observe, but if you think about it for a moment you will notice that doesn't make sense because you will then have to define what it means to observe something. Who observes, what does it mean to have observed something?...almost all our observations are indirect inferences. So what's real then? Is anything?"

Philosophy, as evident here, is most useful useful only in demonstrating the solipsistic tendencies of the human mind. Philosophy is useless to the doing of science. This is particularly true of the deconstructionist drivel that emerged in the 1980s. Taken as a criticism of the widespread abandonment of empiricism by science in the previous decade, it may have had some merit.

However, that critique, of then current practices, morphed into a description of science generally. Not only that, the scientific academy accepted that description as validating their anti-empirical approach. The results are just the stagnation of physics that you rightly complain about.

You can't do meaningful science if you can't come up with working definitions of physical reality, observation, and measurement. What does it mean to say, We use our models (to) describe observations, when you are unable to say what observations are? You've tied yourself into a nihilistic knot that has nothing to do with science.

What differentiates science from philosophy (and mathematics for that matter) is the fact that it is (or was) tethered to observation and measurement. Science is not just about observation and measurement, but that is where it has to begin. To observations and measurements science applies logical analysis (inclusive of mathematics). That is how our body of scientific knowledge was built up. Since the scientific academy cut itself off from science's empirical basis, however, there have been no advances, as you and others have pointed out.

Yes I know, at the limits of our observational range it is difficult, even impossible, to make observations. That, after all, follows logically from the limits. What does not follow logically, is the idea that this realm where we have the least amount of observational evidence to base our theories on, is somehow "fundamental". Furthermore, our heuristically derived mathematics, which reliably predict only statistical outcomes of unobservable and unaccounted for processes, is claimed by many, to say something meaningful about things that it does not describe. That is fundamentally and profoundly illogical.

You're better than that Sabine, you know how to think, but you're hampered by all that unscientific, philosophical baggage that was foisted on you in school. Leave the 'what is reality' crowd to their vacuous musings. The problem with the scientific academy is deeply systemic at this point; it goes far beyond issues of beauty and naturalism. The academy no longer does, or knows how to do, science at the theoretical level anymore.

bud rap, In this matter, you stand with Einstein. It was Bohr, however, who in their famous dialogue asserted "reality is only a word, and we have to learn what the right way is to use that word." To his credit, Einstein with others proposed a physical test of it, which unfortunately wouldn't be implemented til after they'd died, but which to this day offers tighter and tighter constraints. All results support Bohr's position, with whom for this matter it seems Sabine stands (instrumentalist notwithstanding).

Sabine. I really like your article, and I admire your courage in posting it. I am not a physicist, and I can have nothing to say about the substance of what you wrote. I am a historian by training. I do question your use of the word normal.

To me normal is where 95% of humanity are peasant serfs in oligarchical societies, who live on $3/day. In those societies, innovation and progress are maledictions, because they threaten the established social and political order.

The 350 years from the middle of the 17th Century through the end of the were tumultuous, and saw many unprecedented catastrophes. But they also saw the first societies where progress and innovation were welcomed and prosperity was widespread, as was republican government under the rule of law.

But, the law of diminishing returns is inexorable, as are the human traits of folly, greed, and arrogance. The end of our holiday from normal may be upon us.

I am not a physicist, but I do have some basic knowledge of physics. It seems that particle physics was bound to come up against the barrier of asymptotically higher energies required to generate new particles to study, due to the relativistic increase in particle mass with sub-light velocities. There does not seem to be any way to break that physical barrier. The only way out seems to be to gather data by developing more sophisticated measurement techniques in astrophysics/cosmology. The fundamental problem of creating a unified theory in physics is probably because some fundamental data is lacking that is only accessible at extremely high energies which have not yet been produced, and re unlikely or impossible to be produced in the future. Unfortunately, the speed of light is the limiting factor in both particle physics and astrophysics. In the absence of data, theoretical physics can do nothing but flounder in a morass of theories with no way of proving them. It should be obvious that it not that brilliant scholars are lacking, but in the absence of hard scientific data, they are left with no other choice than to come up with wild theories to further their careers.

I go on about the "low hanging-fruit" argument in my book. The brief summary is, it's irrelevant because it doesn't explain why theorists not only have been making wrong predictions for 40 years but more importantly, why they - despite this - simply continue repeating the same thing over and over again, not learning anything. That's why, after all those years, we are still talking about supersymmetry and strings and grand unification. Those were promising ideas in the 1980s. Now it's 2018.

We have problems that are totally solvable, we're just not getting anywhere near solving them because 99% of people waste their time on nonsense.

Of course you do expect progress to slow-down once the easy things have been done. You expect a slow-down in the sense of it requiring more working-hours. Hence I explain in my post that if you consider the slow-down you must factor in the increase in the work force. Best,

I just checked, and from where I sit (Germany, Windows, Chrome) the Kindle version is on offer on the Amazon US page for $13.45. As I already said above, I know it's been published, I know that people have read it, so I am pretty sure it exists. Please note that I have nothing to do with the sales options on Amazon; I neither set up those pages nor can I edit them. Best,

I would find it interesting to collect the general category of the crackpot theories that are submitted over time. Do they change over time? What characteristics are popular to the commoners vs the academics? Certainly the common crackpot theorist is not encumbered by the academic establishment. Perhaps we can learn something from the sample.

Well, in my impression they haven't changed much in the past 10 years. That's probably because not much has changed in the foundations of physics either. These amateur theories are normally collections of buzzwords that people seem to have picked up in the popular science literature.

Though it’s been quite a long time since I worked in High Energy Physics, I do read enough around to convince me that eventually we will really need a near-revolutionary departure from the standard model. This essay by Sabine only reinforces the conviction that new mathematical tools, and not just new concepts, will be needed for the next leap forward. Unfortunately, time and history make their own selections as to what new tools/theories would emerge and when, no matter how hard or how many Physicists push against the existing model boundaries. One may for example be totally right about some new aspect and even offer innovative new explanations for old experimental results, but if the timing is not there, such discoveries will likely fade to obscurity, perhaps to be discovered some day, when the time is right. I am still arrogant enough to think I'll recognize that "inflection point" if I chance to see it (even if the details escape me), so will keep reading about work in the field whenever the opportunity arises.

And yes, sometimes, when I read about this or that new fantastic theory or novel new concepts (love the multi-verse idea, in principle!), I think I can hear The Matrix cracking up laughing in the background. As if it is all a practical joke (and may be we are in a simulation and may be we are not. Not willing to go on a limb either way). At times it does feel as if we are all part of some great game, which is educational for some invisible audience outside the box.

Gravitational wave theories are obviously all false because arbitrary properties have always been used, an assumption that the propagation velocity is c, whereas we know that this cannot be true unless the waves are nothing to do with gravity itself!

Phillip Helberg, I suggest that you are wrong about Vixra, the problem may be some crackpots, but there are a lot of good ideas there too, try these authors:Stephen J. Crothers, Pierre-Marie Robitaille. You may learn something about why Physics is seriously lost.

I can only guess that you may erroneously think that 'c' is defined as being the speed of light, because that's a common mistake. That is not so. 'c' is the speed of massless particles. It just so happens that photons are massless and Einstein originally developed special relativity on the example of electrodyncamics. c is also the speed of gravitational waves because for all we know gravitational waves are massless. This is confirmed by measurements. Gravitational wave theory (I don't know why you think there are several) is obviously correct as it has made predictions that have been confirmed to excellent precision. This blogpost may aid your understanding.

If you can not reach a higher-hanging fruit, that does mean you stop jumping ! ☺ Humans are stubborn animals. They should become really exhausted before they abandon a promising task, and it seems ( as long as somebody else still pays ! :) )that they have not ...

I was out for holiday and late to the conversation. Thanks for having the courage to stir up the pot and deal with the drama.

My first point is there is a lack of new experimental data that conflicts with existing theory. Without conflicting or some new experimental data, isn't it obvious progress will be stagnant? We can't have a bottom up approach that will make progress without new data, and perhaps there isn't much more to be found at the bottom. A way forward is to tackle the problem with emergent or even top down approaches. However, in my opinion most physicist don't believe in top down or even emergent physics and there are no easy experiments to verify them. Imagine an experiment to validate how something is emergent, such as consciousness...

My second point is that in the big picture humans have reached an intellectual capacity problem. We're going to be stuck for quite awhile -- 100 years or more. One way out is to augment ourselves with longer lifespans and machine intelligence.

My last point is I am not sure I agree that we can dismiss Machine Learning having been already tried as a way forward, certainly the most modern techniques could not have been applied but in the last few years. Modern ML techniques combined with quantum computing should certainly be attempted as a way forward for the next 10 years at least, especially for particle physics where the data set is tremendous.

I suspect there are many contributions to why no headway is being made, but I think the most significant is conceptual. Look at dark matter/modified gravity. Neither explanation seems to work entirely satisfactorily as yet. The modified gravity runs into the conceptual problem of how will it work? For example, the inverse square law conceptually follows from a surface of some form of messenger "radiating" from the source, and whether that is what actually happens is less important than it gives a relationship that works, at least in our solar system. But what underpins some other relationship, and why does it change? If one had an idea there, it might lead to a solution, but as far as I can tell, so far that has eluded us.

For dark matter, it doesn't seem to do anything else, so we have one postulate for one effect, and we cannot find a test. We have had guesses, like WIMPS, but the guesses seem to be wrong. So, here and elsewhere, I think it is the spark of inspiration that is missing, and without an unambiguous piece of data that must be explained, this is very difficult. Einstein had the constancy of c, but so did the others at the time. Even when the unambiguous clue is present, it is not easy. Without it, it is far more difficult.

The perfect example is Galaxy rotation relations. There are a lot of rules taken from observations eg. Renzo's Rule.

There are peer reviewed papers that fit the maths, resolve virtually all the details regarding Dark Matter and Dark Energy. They are not my papers, so I am not self promoting here. I just think some of your readers may like to be aware that there are some interesting alternatives to General Relativity floating around the Peer Reviewed Journals.

You appear to be lumping some peer reviewed ideas/theses that deal with some of these issues along with "personal theories". Are there that many ideas that pass peer review, that you consider any non main stream theory as noise? The thesis of your book appears to be that it is the main stream foundationalism that has gone off course.

"The thesis of your book appears to be that it is the main stream foundationalism that has gone off course."

The reason I focus on main stream topics is that those are topics the reader is likely to have heard about.

As I explain very clearly in my book, math is necessary. Indeed, as I point out, the problems that we have in the foundations of physics could have been prevented with more rigorous use of mathematics. I don't know exactly what you mean by main stream, but the amateur "theories" that I get are nowhere near the present level of quality in the field and represent a step back, not a step forward. This is not to say that more math is necessarily better. Just because you can calculate something doesn't mean it actually describes anything we observe. Best,

Sabine, I m not sure what you mean by "more rigorous use of mathematics". If it means "correctly using maths" that is obviously right, but some seem to think the the more sophisticated the maths the better. In my opinion, the correct use of simple maths is perfectly legitimate. I regard maths as an essential tool, but it is just that - a tool. For me, nature is not simply maths, and all maths do is describe it. It is true that just because you can calculate something does not mean that it it accurately describes the underlying aspect of nature, but it is better than if you cannot. My view is that any calculation does not get you any further unless you can accurately calculate something that is independent of what the "theory" was designed to calculate, in other words, some output should be additional to and independent of any input.

Well, yes, of course you should correctly use math, but that's not my point. You should use it to begin with. Take the issue with naturalness that I go on about in my book. If you try to identify a mathematical problem with an unnatural theory you will find that there is none. Likewise, I think it's a waste of time to complain about what's supposedly ugly about quantum mechanics if you cannot mathematically formulate a problem. Ditto with unification. It's nice, but not mathematically necessary. Best,

Hi Sabine,Well, everyone now knows the difference between the dark matter approach to the Galaxy Rotation problem and the MOND approach. This thanks to your detailed videos on the subject.

The maths of MOND is more predictive in that for a given galaxy, you can guess an appropriate value of a0 and predict the velocity of stars *before* they are measured. The MOND maths is the *predictor* of something that is then measured that makes a good test or confirmation of the thesis behind the maths.

However the dark matter is the *predicted* something that does not in turn tell us anything else in advance of measuring it. Certainly not in the decades since its hypothesis was made and doesn't appear to numerically predict anything that we can strictly test independently.

Whether it is an "amateur" theory that can explain why the MOND maths works, or whether it is judged as "quality" - To me, an idea that can be checked quickly that it fits the maths is worth pursuing. Much more so if it has passed peer review. The fact that I personally know about just such peer reviewed papers existing, and that you do not mention the perfectly reasonable and quality controlled arguments in them, make them conspicuous by their absence.

This leads me to suggest that the really good alternatives that resolve many of the issues of foundational physics are hiding in amongst a multitude of "lost in math" papers.

This by design - There appears to be no incentive for you or anyone else that have good reputations in physics, to highlight such possible solutions.

"I just think some of your readers may like to be aware that there are some interesting alternatives to General Relativity floating around the Peer Reviewed Journals."

Assuming that statement is true, and that these theories fit the experimental data well, I wonder if this highlights a very serious possible reason for the stagnation.

Once a scientific theory becomes accepted, another theory that explains the same data equally well is unlikely to replace it. It seems to me that this isn't really logical. If there are multiple theories to choose from, selecting the one that was invented first, can obviously set science on the wrong course!

I guess it would be more logical try to resolve that problem before moving on with one of those theories, chose by random!

On viXra, Phillip Helbig, and David: if you have an hour or so of your life free, by all means read a sample of what’s on viXra. Perhaps check out David’s recommendations for yourself. Then decide how much effort would be needed to find good new ideas (on the foundations of physics) in that trash heap.

And David: if you think those two authors have ideas worth developing, why not go ahead and develop them yourself?

/"I just think some of your readers may like to be aware that there are some interesting alternatives to General Relativity floating around the Peer Reviewed Journals."

References, please.

Sure, there are alternative theories to GR. The question is are there any which are not ruled out by observation which explain things which GR doesn't and/or, at the risk of offending Sabine, have more beautiful math?

"The problem is also not that we lack data. We have data in abundance. But all the data are well explained by the existing theories"

Would data from the very early universe, gravitational waves detected by a LIGO in space, say, give theorists something to get their teeth into, in terms of a combined QM and GR theory? Or would a LIGO in space not give any more information than LHC or the like? Does the fact that Hawkings' and Turok's mathematical extrapolations back to the purported beginning of the observable universe leading to predictions of different types of universe (one "curved off", one bouncing), suggest further observational data is needed to resolve the question?

Should the string in String Theory be renamed "God", and the String Theorists moved into the Theology department?

LIGO does not collect data from the early universe, it's data from the late universe so to speak. It is possible that LIGO captures a signal related to quantum gravity, but I consider it extremely unlikely because the theories which predict this are not very plausible. I explained this here. However, some people think that it is plausible, see eg here.

Cheers."Especially interesting for quantum gravity are the primordial gravitational waves that were around already in the early universe. ... however , measuring primordial gravitational waves is really hard. "Why really hard? Because they are "faint"?Will there be more chance with a Space Interferometer due to less noise?That stuff about waves possibly bouncing between a black hole horizon and proton sphere from Perimeter and Toronto is amazing. As the Major said in Fawlty Towers, "I didn't know Canadians were as clever as that!"

BICEP tried to measure primordial gravitational waves. Brian Keating wrote a whole book about why that's difficult, which I recommend you read if you are interested in the topic. It's a weak signal, worse, no one knows exactly how weak, and if you measure it indirectly through CMB polarization there's the foreground contamination from the Milky Way. A space-based gravitational wave interferometer would help because in that case you can directly measure it.